SYNCOPE RECURRENCE CAN BETTER BE PREDICTED BY HISTORY THAN BY HEAD-UPTILT TESTING IN UNTREATED PATIENTS WITH SUSPECTED NEURALLY-MEDIATED SYNCOPE

Background Head-up tilt testing is widely used in the evaluation of pa tients with suspected neurally mediated syncope. Although it remains u nclear which patients require medical therapy to prevent recurrent syn cope, most centres initiate empiric medical therapy in all patients in whom neurally mediated syncope has been diagnosed. To determine the n atural history of this condition, we followed 80 untreated patients. M ethods All 80 study patients fulfilled the following inclusion criteri a: (I) greater than or equal to 1 syncope in the upright position, (2) absence of structural heart disease, (3) unremarkable work-up for oth er known causes of syncope. Thirty-nine patients had a history of one episode of syncope (group A) and 41 greater than or equal to 2 episode s of syncope (group B). Head-up tilting was performed in all patients at 60 degrees for a maximum of 45 min without medical provocation ('We stminster Protocol'). Results Suspected neurally mediated syncope coul d be reproduced by tilt testing in four of 39 patients from group A vs 10 of 41 patients from group B (10% vs 24%, P=0.1). Independent of th e result of head-up tilt testing, all patients were prospectively foll owed without medical therapy. During 23 +/- 8 months follow-up, syncop e recurred in four of 39 group A patients vs 22 of 41 group B patients (10% vs 54%, P<0.05). The incidence of syncope during follow-up was n ot significantly different between patients with and without positive baseline tilt test (43% vs 30%, P=ns). Conclusions (1) 90% of patients with a single episode of syncope remain free of recurrent syncope wit hout medical therapy irrespective of the result of tilt testing. (2) A bout half of patients with a history of greater than or equal to 2 syn copal episodes have recurrent syncope and, thus, may be appropriate ca ndidates for prophylactic medical therapy. (3) Although head-up tilt t esting at 60 degrees for up to 45 min does not appear to be useful to predict recurrent syncope in untreated patients, it is still a useful test in its evaluation.